Yeah OK that makes it a little easier Geoff.
There are a few aftermarket R33 big brake kits on eBay from D2 and Ksport, running 2, 4, 6 or 8 piston calipers and right up to 400mm. Pretty bonkers for rear brakes!
My engineer wasn't too keen on going down that path. ie, questions about quality and safety.
Edit: plenty of Brembo kits from international sellers too. Maybe that's an avenue, being an established brand? $5k delivered, ouch